The energy source structure of our country is rich in coal but poor in natural gas or petroleum. With the continued progress of social economy and increasing improvement of people's living standard, the demand of energy source is daily on the increase, especially in the field of cleaning civil fuel and vehicle fuel, the increasing rate is much faster. Therefore, to base ourselves upon China and vigorously develop coal-based synthetic liquid alternative fuels will be one of the important routes to address the problem of the safe supply of energy sources. Compared to other coal-based fuels, coal-based oxygenated fuels, i.e., methanol fuels and dimethyl ether fuels, not only possess remarkable advantages of technique and economy, but also make full utilization of the three elements of C, H, O in coals, which can achieve the sustainable development of the resources, energy sources, environment and economy.
In recent years, much attention is paid to slurry bed reactors due to their advantages of favourable heat transfer, easy of temperature constant operation, and especially suitability for the poly-generation process of heat, electrical and chemical products. Slurry bed reactors are one of the most advanced reactors for producing alcohols and ethers which are currently researched and developed. However, the stability of catalyst is a main factor influencing the normal operation of the synthesis of alcohols and ethers in a slurry bed reactor, thus how to enhance the stability of catalyst is becoming the focus of research. Currently, many of patents in this field focus on the selection of process conditions, the reconstruction of reactors, and the improvement of catalysts, for example, CN131108C, CN1139427C, CN1043739C, CN1043409C, CN1169618C, CN1172893C, CN1039224C, CN1085647C, CN1202061C, CN1247506C, etc., while there is little report on the technique for producing a catalyst specific for the use characteristics of slurry bed reactors. By far, most catalysts used in slurry bed reactors are produced by firstly forming a solid catalyst, crushing and milling it, and then dispersing it into an inert medium to produce a slurry. Only Chinese Patent Application No. 200410012537.6 owned by ourselves discloses a slurry catalyst having similar phase structure and pore structure of a solid catalyst and formed directly from raw materials, as well as its preparation method. The method comprises firstly preparing a gel containing a catalyst comprised of CuZnAl, CuZr and CuTi, soaking thus obtained gel in an organic solvent such as an alcohol, a ketone, an ester, or the like, then dispersing the soaked gel into an organic medium, and then heat treating it at an atmosphere of mixed N2 and O2 within a certain temperature range. Further study reveals that when the catalysts of CuZnAl and CuZr are used in a slurry bed reactor to synthesize methanol and dimethyl ether, the catalyst CuZnAl has good activity but poor rheological behavior and wear resistance whilst the catalyst CuZr has good rheological behavior and wear resistance but poor activity. Furthermore, it is found that both the gel surface treatment process involved during preparation of the catalyst for a slurry bed reactor and the heat treatment atmosphere of the gel dispersion have significant effect on the properties of the catalyst.